dev.to staff

Posted on Feb 12, 2020

Daily Challenge #185 - House Numbers Sum

#challenge

Setup

A boy is walking home from school. To make the walk more enjoyable, he decides to add up the numbers of the houses he passes during his walk. Unfortunately, the numbers won't appear to him in any specific order, since he's regularly taking turns.

At some point during the walk, the boy encounters a house marked number 0. This surprises him so much that he stops adding the numbers after that house to the total.

For the given array of house numbers, determine the sum that the boy will get. There will always be at least one number 0 house on the path.

Examples

inputArray = [5, 1, 2, 3, 0, 1, 5, 0, 2] => 11

inputArray = [1, 4, 34, 124, 2, 0, 14, 51] => 165

Tests

inputArray = [5, 1, 2, 3, 0, 1, 5, 0, 2]

inputArray = [4, 2, 1, 6, 0]

inputArray = [4, 1, 2, 3, 0, 10, 2]

Good luck!

This challenge comes from myjinxin2015 on CodeWars. Thank you to CodeWars, who has licensed redistribution of this challenge under the 2-Clause BSD License!

Want to propose a challenge idea for a future post? Email yo+challenge@dev.to with your suggestions!

Top comments (8)

Valts Liepiņš • Feb 12 '20

My original solution in Ruby

def houseNumSum arr
    arr.reduce(0) do |result,x|
        return result if x == 0
        result += x
    end
end

and after being inspired by Craig's solution:

def houseNumSum arr
    arr.take_while {|x| x != 0}.sum
end

Craig McIlwrath • Feb 12 '20

Simple Haskell solution

houseSum :: (Eq a, Num a) => [a] -> a
houseSum = sum . takeWhile (/=0)

Madza • Feb 12 '20

const sum = arr.slice(0, arr.indexOf(0)).reduce((a, b) => a + b, 0);

SavagePixie • Feb 12 '20

Elixir

defmodule Challenge do
  def housenumsum([ 0 | _tail ]), do: 0
  def housenumsum([ head | tail ]), do: head + housenumsum(tail)
end

Vidit Sarkar • Feb 12 '20

C++ solution

int sumHouse(vector<int> numbers){
    int sum = 0;
    for(int i: numbers){
        if(i==0)
            return sum;
        sum += i;
    }
}

Nicolas Hervé • Feb 12 '20

Javascript

const sum = (arr) => arr.slice(0, arr.indexOf(0)).reduce((acc, curr) => acc + curr, 0);

testingpro • Feb 12 '20 • Edited

JavaScript


const sum = inputArray =>
inputArray.slice(0, inputArray.indexOf(0)).reduce((a, b) => a+b);
sum(inputArray);

Matt Ellen-Tsivintzeli • Feb 13 '20

If a test case doesn't have an expected output, is it really a test case?

Also, what did the boy do for houses with numbers like "14A" or houses that have names, and no number?

DEV Community

Daily Challenge #185 - House Numbers Sum

Setup

Examples

Tests

Top comments (8)

Read next

Converting any Arabic font to TechArabic

Firebase Integration Challenges in React Native

Learn how to create a sidebar navigation with Tailwind CSS and JavaScript

Automating Docker Management with Terraform